---
title: "Mastra"
sidebarTitle: "Mastra"
description: "End-to-end example of calling external tools with the Mastra SDK."
---

## Setup

```bash
npm i @mastra/core @nangohq/node
```

<Tip>
This example uses the Node SDK, a lightweight wrapper over Nango’s REST API. The same flow works in any language by using the [API reference](https://nango.dev/docs/reference/api/authentication).
</Tip>

**Requirements:** 
- A Nango account with a Hubspot integration configured and the `whoami` action enabled.
- An OpenAI account (or another LLM provider).

## Usage

Example of a basic tool that calls an external API (Hubspot):

```ts
import { Agent } from "@mastra/core/agent";
import { createTool } from "@mastra/core/tools";
import { Nango } from "@nangohq/node";

export async function runMastraAgent() {
  if (!process.env.OPENAI_API_KEY) {
    console.log("Missing environment variable: OPENAI_API_KEY.")
  }

  const nango = new Nango({ secretKey: process.env.NANGO_SECRET_KEY! });

  const userId = "user1", integrationId = "hubspot";

  // Step 1: Ensure the user is authorized
  console.log("🔒 Checking API authorization...")
  let connectionId = (await nango.listConnections({ integrationId, userId })).connections[0]?.connection_id;

  // Step 2: If the user is not authorized, redirect to the auth flow.
  if (!connectionId) {
    const session = await nango.createConnectSession({
      allowed_integrations: [integrationId],
      end_user: { id: userId },
    });

    console.log(`Please authorize the app by visiting this URL: ${session.data.connect_link}`);

    const connection = await nango.waitForConnection(integrationId, userId);
    connectionId = connection!.connection_id;
  }

  // Step 3: Send a prompt to your model.
  const agent = new Agent({
    name: "Hubspot Agent",
    instructions: "You are a helpful assistant that can access Hubspot data.",
    model: "openai/gpt-4o",
    tools: {
      who_am_i: createTool({
        id: "who_am_i",
        description: "Get the current user info.",
        execute: async () => {
          // Step 4: Execute the requested tool with Nango.
          return await nango.triggerAction(integrationId, connectionId, "whoami");
        },
      }),
    },
  });

  console.log("🤖 Agent running...")
  const response = await agent.generate("Using the who_am_i tool, provide the current user info.");

  console.log("✅ Agent retrieved your Hubspot user info:", response.text);
}
```

<Tip>
You can let agents or models introspect available tools and their specifications by calling this [endpoint](/reference/api/scripts/config). Your model can then automatically decide which tool to call.
</Tip>